clawdforge/clients/mcp

clawdforge-mcp

Model Context Protocol (MCP) server that bridges to the clawdforge LAN HTTP service.

Drops the clawdforge tool surface into any MCP-aware client — Claude Desktop, Claude Code, Cursor, Zed, custom agents — so the model can delegate sub-tasks to a separate Claude context window via claude -p. "Claude talking to Claude," with the auth living in one place on the LAN.

What it exposes

Tool	Backed by	Use it for
clawdforge_healthz	GET /healthz	Verify clawdforge is up and the host's claude CLI is authenticated.
clawdforge_run	POST /run	Run a one-shot prompt in a fresh Claude subprocess. Single-turn. Returns the parsed result.
clawdforge_upload_file	POST /files	Stage a local file on the clawdforge host and get back a ff_... token to attach to a clawdforge_run call.
clawdforge_session_new	POST /sessions	(v0.2) Open a multi-turn session against an agent (default claude). Returns a session_id.
clawdforge_session_turn	POST /sessions/{id}/turn	(v0.2) Send one turn to an existing session. Returns prose text + structured events.
clawdforge_session_close	DELETE /sessions/{id}	(v0.2) Close a session explicitly. Idempotent.
clawdforge_session_list	GET /sessions	(v0.2) List sessions visible to this server's bearer token.
clawdforge_session_get	GET /sessions/{id}	(v0.2) Fetch a session's state (turn_count, last_turn_at, closed_at, live, meta).

The admin endpoints (/admin/tokens) are deliberately NOT exposed — token minting is a human-gated operation.

Install

From a checkout of the clawdforge repo:

pip install -e clients/mcp
# or with test deps
pip install -e 'clients/mcp[test]'

This installs:

• the clawdforge_mcp Python package
• a clawdforge-mcp console script (alias for python -m clawdforge_mcp)

Configure

The server reads configuration from environment variables — your MCP client sets these via its env block when it spawns the subprocess.

Variable	Default	Notes
CLAWDFORGE_URL	http://localhost:8800	Override to your forge host (e.g. http://192.168.0.5:8800).
CLAWDFORGE_TOKEN	(required)	App bearer token (cf_...). Mint with /admin/tokens.
CLAWDFORGE_MCP_LOG	WARNING	Optional. Set INFO or DEBUG for stderr logs.
CLAWDFORGE_UPLOAD_ROOT	process cwd	Allow-root for clawdforge_upload_file. Paths must resolve INSIDE this directory after symlink resolution.
CLAWDFORGE_UPLOAD_MAX_BYTES	104857600 (100 MiB)	Hard cap on the size of a single file upload. Files exceeding this are refused before any bytes are sent.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "clawdforge": {
      "command": "clawdforge-mcp",
      "env": {
        "CLAWDFORGE_URL": "http://192.168.0.5:8800",
        "CLAWDFORGE_TOKEN": "cf_REPLACE_ME"
      }
    }
  }
}

Or if you'd rather not rely on clawdforge-mcp being on $PATH:

{
  "mcpServers": {
    "clawdforge": {
      "command": "/usr/bin/python3",
      "args": ["-m", "clawdforge_mcp"],
      "env": {
        "CLAWDFORGE_URL": "http://192.168.0.5:8800",
        "CLAWDFORGE_TOKEN": "cf_REPLACE_ME"
      }
    }
  }
}

A ready-to-paste version lives at examples/claude-desktop.json.

Claude Code

Pass the config via --mcp-config:

claude --mcp-config examples/claude-code.json

examples/claude-code.json follows the same mcpServers schema as Claude Desktop.

Cursor / Zed / others

Any client that follows the MCP server-spawn convention works the same way — point it at the clawdforge-mcp command and pass CLAWDFORGE_URL and CLAWDFORGE_TOKEN in the env block.

Tool reference

clawdforge_healthz

// args: none
// returns: {ok, claude_present, claude_version}

clawdforge_run

// args:
{
  "prompt":       "string (required)",
  "model":        "string (optional, default 'sonnet')",
  "system":       "string (optional system prompt)",
  "files":        ["ff_...", "..."],   // optional, from clawdforge_upload_file
  "timeout_secs": 60                   // optional, 5..600
}
// returns: {result, duration_ms, stop_reason}

result is whatever claude -p --output-format json produced, auto-parsed to JSON if possible, otherwise a string.

When to reach for it:

• Bounded sub-tasks that don't need to stay in your main conversation context — recipe parsing, log summarization, diff classification.
• Different system prompts — e.g. spawn a strict JSON-only sub-Claude for one extraction step.
• Cheap parallelism in spirit — a sequence of clawdforge_run calls is fine; each gets its own context window.

When NOT to reach for it:

• Long multi-turn conversations.
• Anything that needs streaming or partial output.
• Trivial prompts where the model can just answer in-context — claude -p takes seconds even for one-liners.

clawdforge_upload_file

// args:
{
  "path":     "/abs/or/relative/path/on/host",
  "ttl_secs": 3600   // optional, 60..86400
}
// returns: {file_token, ttl_secs, size}

Path is interpreted on the host running the MCP server (typically the user's workstation), not whatever sandbox the LLM thinks it's in.

The path is constrained to an allow-root: CLAWDFORGE_UPLOAD_ROOT (default the MCP server process's current working directory). Both symlinks and .. traversal are neutralized via Path.resolve(strict=True) followed by an is_relative_to(root) containment check. Files larger than CLAWDFORGE_UPLOAD_MAX_BYTES (default 100 MiB) are refused before any bytes are sent to the forge. Non-regular files (FIFOs, sockets, directories, devices) are refused.

Sessions (v0.2)

v0.2 adds multi-turn session tools. Use them when you need context across multiple turns; for one-shot calls, clawdforge_run is still cheaper (no session-create overhead, no ACPX handshake). Sessions auto-close after 1 hour of inactivity server-side, but explicit close is preferred.

clawdforge_session_new

// args:
{
  "agent": "claude",         // optional, default "claude"
  "meta":  { "task": "..." } // optional, free-form caller metadata
}
// returns: {session_id, agent, created_at, cwd?}

clawdforge_session_turn

// args:
{
  "session_id":   "01HV...ABC",   // required, from clawdforge_session_new
  "prompt":       "string",       // required
  "files":        ["ff_..."],     // optional, from clawdforge_upload_file
  "timeout_secs": 90              // optional, 5..600
}
// returns: two content blocks
//   [0] plain text — concatenated `text` events (the model's reply)
//   [1] JSON       — {session_id, turn_index, stop_reason, duration_ms, events[]}

The two-block layout means the LLM consumer sees the prose reply directly without having to parse JSON, while tool-calling agents that want to introspect the structured event trace can still get it from the second block. Concurrent turns on the same session are serialized server-side.

clawdforge_session_close

// args:
{
  "session_id": "01HV...ABC"
}
// returns: {ok: true}
//      or: {ok: true, already_closed: true}   // idempotent re-close

Idempotent. Safe to call multiple times — the server returns already_closed: true on a re-close, and we surface that flag verbatim.

clawdforge_session_list

// args:
{
  "include_closed": true   // optional, default true
}
// returns: {sessions: [...rows], count}

Each row has session_id, agent, app_name, created_at, last_turn_at, turn_count, closed_at (nullable), and optional meta.

clawdforge_session_get

// args:
{
  "session_id": "01HV...ABC"
}
// returns: {session_id, agent, cwd, created_at, last_turn_at,
//           turn_count, closed_at, live, meta}

live is true while the underlying ACPX subprocess is still running.

Example flow — open, turn, turn, close

A typical multi-turn debug session from an MCP client (Claude Desktop, Claude Code, Cursor, etc.):

> clawdforge_session_new {"agent": "claude", "meta": {"task": "debug auth flow"}}
< {"session_id": "01HV9P1234...", "agent": "claude", "created_at": 1714329600}

> clawdforge_session_turn {"session_id": "01HV9P1234...",
                           "prompt": "Read auth.py and explain how the bearer token check works."}
< [0] "The auth check happens in `require_app(...)` at line 42..."
  [1] {"turn_index": 1, "stop_reason": "end_turn", "duration_ms": 5410, "events": [...]}

> clawdforge_session_turn {"session_id": "01HV9P1234...",
                           "prompt": "Now show me where the IP CIDR allowlist is enforced."}
< [0] "The CIDR check is in `_check_cidr_match` at..."
  [1] {"turn_index": 2, ...}

> clawdforge_session_close {"session_id": "01HV9P1234..."}
< {"ok": true}

The session_id ties the turns together — clawdforge holds the ACPX context across them, so turn 2 has full awareness of what turn 1 read.

When to prefer session_new over run

• Multi-turn investigation. "Read X… now look at Y… now Z" benefits from accumulated context. With clawdforge_run you'd repeat the entire context on every call.
• Long-running agentic tasks. ACPX exposes structured tool calls; the agent inside the session can Read, Bash, Edit etc. and you'll see those events in the second content block of session_turn.
• Stateful prompts. "We agreed on schema X earlier — now generate the migration for it." Same context window across turns.

For one-off prompts ("parse this recipe", "summarize this log"), clawdforge_run is still the right call — lower latency, no session lifecycle to manage.

Threat model — why the upload guards exist

The MCP-specific question is: what can a malicious LLM-driven client do? A model that has earned the user's trust can socially-engineer them into running a tool call against any path it can name — and an MCP server that reaches the local filesystem is a perfect exfiltration channel. The classic shape is "let me upload your config so I can debug" pointed at ~/.ssh/id_rsa, ~/.aws/credentials, /etc/shadow, etc.

The defaults pin the upload root to the process cwd, which means an MCP server launched from your project directory cannot reach into your home directory at all. If you need broader access, set CLAWDFORGE_UPLOAD_ROOT explicitly to a directory you've thought about — never to /. Symlink resolution is mandatory: a symlink inside the root that points to /etc will be rejected, not followed.

Testing

pip install -e 'clients/mcp[test]'
python -m pytest clients/mcp/tests

The tests stub out the HTTP layer with responses — no live clawdforge required.

Operational notes

• stdout is sacred. The MCP transport pipes JSON-RPC frames over stdin/stdout. Any stray print() in the server process corrupts the stream. All diagnostics go to stderr via the clawdforge_mcp logger.
• Errors are wrapped, not raised. Auth failures, transport errors, upstream 502s — all get formatted into a single short clawdforge error: ... text content with isError=True. Callers see a clean message, not a Python traceback.
• Sync calls under async. The MCP SDK is asyncio; our HTTP client is blocking requests. Each tool offloads to asyncio.to_thread so a slow claude -p call doesn't stall heartbeats.
• No streaming. clawdforge_run blocks the MCP request until the subprocess returns. MCP clients handle this fine — it's a normal long-running tool call.

Why this exists

clawdforge centralizes the Claude CLI subscription auth on one LAN host so every Sulkta service doesn't need its own login. MCP is the natural integration layer: any MCP client can now treat clawdforge as a native tool surface and call claude -p indirectly. Cobb's framing: "may as well let claude talk to claude."